Over the past month or so there has been a lot of talk about postdocs, whether it's why people do them, the purpose of them or why some think they suck. In my field there is pretty much no getting around doing a postdoc if you want to do the whole TT thing, and frankly, I think that's a good thing. No matter how much you think you know about research and being a PI by the end of your PhD, the time as a postdoc is valuable in learning how much you really don't know. On top of that, being a postdoc should be one of the most exciting research times of your career.
The biggest complaints I hear about postdocing are 1) Money, 2) moving around and 3) lack of independence.
Money. This may be unpopular, but if you are in this business to get rich you might as well leave now. Yeah, PDFs typically make $35K - $50K, depending on the field and that isn't a ton of money given the training they have had to that point, but get over it. You're being paid to do research, and in most cases, have no other distractions. Assuming you have picked a research topic you enjoy, this is a pretty good deal. Personally, I would seriously consider the pay cut to be doing just research at this stage.
Moving around. Yup, the academic lifestyle can be somewhat nomadic and that can put a strain of relationships and make for difficult logistics. Because of that, a lot of people try and limit their geographic search, sometimes unreasonably. Personally, I would (and did) take the opposite approach and look for a postdoc in a completely unfamiliar place where you might never chose to settle. Why? Because a postdoc can be a lot more than just a job experience. I have numerous friends who are doing postdocs all over the world and the happiest of them are the ones that chose a place totally different from what they were used to. Maybe this wouldn't work in all fields, but there are plenty of excellent labs in other countries and you would be amazed how helpful international experience can be for collaborations. Not to mention that being in an unfamiliar place encourages one to go out and explore. Getting out of the lab for fun can be a good thing.
Lack of independence. Now I know that lots of people get into situations where they feel taken advantage of or where they are stuck doing projects they don't care about. That is why it is critical to do your homework ahead of time and know enough about the supervisor whose lab you are joining to determine if you can work with them and get the mentoring you need. Don't just take a position in any lab doing something remotely close to what you like. Talk to other trainees in the lab! Talk to former trainees. Is the lab a good place to develop as a scientist? That information can be FAR more important than the project. Put yourself in a place to succeed.
Obviously, this isn't a fool proof way to a happy postdoc, but give yourself the best shot you can. Expand you research horizons with something different from your PhD and do it in a fun place, both socially and scientifically. A postdoc can be one of the best times of your career.